In particular, this invention relates to a tilt apparatus for the cab of an excavator/digger. However this should not be seen as limiting as the present invention may be applied to the cabs of the other vehicles.
For ease of reference only, the vehicle will now be referred to as being an excavator.
Existing tilt apparatus for leveling the cab of an excavator all suffer from a number of drawbacks.
U.S. Pat. No. 4,679,803 (US'803) provides a tilt apparatus for a cab, but this unit due to its construction, needs to be fitted to a purpose built chassis and this cannot be retrofitted to existing excavators.
PCT/NZ1998/00092 (PCT'00092) is an earlier patent application by the present inventor and describes a tilt apparatus which is capable of being retrofitted to an excavator.
However, this tilt apparatus is not configured to allow for substantially continuous adjustment of the tilt apparatus as inclination sensors are not employed. Furthermore, this tilt apparatus does not have the ability to detect and display the relative position of the track chassis to the cab.
Moreover, the inventor has discovered that both the inventions described in US'803 and PCT'00092 do not provide a tilt apparatus capable of automatically tilt leveling the cab whilst the excavator is in transit. In particular, they do not provide any indication as to whether a slope is too steep for the unit to operate. Therefore, the units described in these patent specifications are within a short period of time, prone to mechanical failure if operated when in transit. This is because there is no control over the hydraulics of the tilt apparatus when approaching the edge of the stroke limit of a ram. Accordingly, on steep slopes outside the range of the tilt apparatus' ability to level the cab the rams do not slow down as they reach their limit.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents from part of the common general knowledge in the art, in New Zealand or in any other country.
It is acknowledged that the term ‘comprise’ may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising’ is used in relation to one or more steps in a method or process.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.